Downhole Removable Cage with Circumferentially Disposed Instruments

ABSTRACT

A downhole drill string component is disclosed comprising a substantially cylindrical cage with a hollow bore. An inner diameter of the cage is slideably connectable to a mandrel. A stab connection originates from one end of the cage and a plurality of downhole drill string instruments is circumferentially disposed around an outer diameter of the cage.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/341,771 filed on Dec. 22, 2008 and entitled ‘DownholeInduction Resistivity Tool’ which is a continuation-in-part of U.S.patent application Ser. No. 11/776,447 filed on Jul. 11, 2007 andentitled ‘Externally Guided and Directed Field Induction ResistivityTool’ which claims priority to Provisional U.S. Patent Application No.60/914,619 filed on Apr. 27, 2007 and entitled ‘Resistivity Tool.’ Thisapplication is also a continuation-in-part of U.S. patent applicationSer. Nos. 11/676,494; 11/687,891; 61/073,190. All of the above mentionedreferences are herein incorporated by reference for all that theycontain.

BACKGROUND OF THE INVENTION

The present invention relates to downhole drilling, specificallydownhole drilling technology for oil, gas, geothermal and horizontaldrilling. More specifically, the present invention relates to downholedrill string components and connections between components. Also, thepresent invention relates to communication between uphole and downholecomponents.

Downhole instruments may be used to analyze downhole formationcharacteristics such as porosity or density or to locate resourcedeposits in a formation. The assembly of a drill string comprising aplurality of instruments often involves individually electricallyconnecting the instruments. In many cases, each instrument must be wiredseparately. Downhole drill strings with multiple instruments cancomprise a multiplicity of wires, often increasing the complexity ofwiring downhole instruments to the desired location within the drillstring. The overall efficiency of this method of wiring may be inferiorto an apparatus that comprises a reduction of the number of wiresinvolved. Additionally, the ability to simultaneously electricallyconnect the plurality of instruments to a power source, processor ordownhole network may reduce the assembly time.

A common practice in the art involves exciting one instrument oftencircumferentially wrapped around the drill string and used to gatherborehole data downhole. Exciting this single instrument generally doesnot allow for only a portion of a borehole to be analyzed to determinedownhole characteristics.

U.S. patent application Ser. No. 11/776,447 to Snyder, which is hereinincorporated by reference for all that it contains, discloses in oneaspect an induction resistivity tool incorporated into a downhole toolstring comprising an outer wall of a downhole component comprising anouter diameter and at least one induction transmitter assembly disposedalong the outer diameter. The at least one transmitter assemblycomprises at least one induction transmitter coil wound about at leastone core. The at least one transmitter coil is adapted to project aninduction signal outward from the outer wall when the at least onetransmitter coil is carrying an electrical current. The transmitterassembly is adapted to create electromagnetic fields that originate theinduction signal from outside the outer wall and substantially preventthe signal from entering the outer wall.

U.S. Pat. No. 5,045,795 to Gianzero, et al, which is herein incorporatedby reference for all it contains, discloses a coil array which isinstalled on a MWD drill collar for use in a resistivity logging system.The drill collar is provided with upper and lower coil support rings.These are toroids which support individual coil segments, and areconnected by suitable magnetic shorting bars. The coil segments andshorting bars inscribe a specified solid angle or azimuthal extent. Byconnecting the outputs of the several coils through a combining circuit,the coils on a single coil form can be connected in series additive, orsubtractive relationship. Through the use of two such coil forms withaligned coils on each, an azimuthally oriented window is therebydefined. By proper switching multiple azimuthally oriented windows canbe made operative so that there is an azimuthal orientation to thecurrent flow pattern relative to the MWD resistivity logging tool.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the invention a downhole drill string componentcomprises a substantially cylindrical cage. The cage has a hollow bore,with an inner diameter and an outer diameter. The inner diameter of thecage is slideably connectable to a mandrel. A stab connection originatesfrom one end of the cage. A plurality of downhole drill stringinstruments is circumferentially disposed around the outer diameter ofthe cage.

In several different embodiments of the present invention the pluralityof downhole drill string instruments may be induction receivers,induction transmitters, Halbach arrays, batteries, nuclear tools,acoustic tools, similar downhole instruments known in the art, or anycombination of such instruments. The cage may comprise a stab connectiondock adapted to receive a stab connection on the opposite end from thestab connection, thus allowing for several embodiments of the presentinvention to be interconnected, directly or with other elements inbetween.

The cage may comprise a shell disposed circumferentially and at leastpartially along an inner cylinder that sits intermediate the downholedrill string instruments and the inner cylinder. The shell may have aplurality of recesses adapted to receive downhole drill stringinstruments. The shell may be segmented and the segments may be joinedthrough a joining mechanism. The joining mechanism may comprise bolts,nuts, latches, screws, clips, hinges, adhesives, metallic bondingagents, welds, pins, other joining elements known in the art orcombinations thereof. The cage may have a seal on either end that mayact to restrict access of the drilling fluid into certain areas.

The cage may comprise an alignment key proximate the stab connection toprotect the stab connection while it is being connected to a stabconnection dock. The cage may also comprise a plurality of groovesdisposed circumferentially around the cage that match with a pluralityof rods on a stab connection dock or other downhole component. Thesegrooves and rods may provide torsional strength and further protect thestab connection.

The stab connection may electrically communicate with a multiplexor, maybe uniquely addressable, and may comprise a processing unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side-view diagram of an embodiment of a tool stringsuspended in a borehole.

FIG. 2 is a side-view diagram of an embodiment of a tool stringcomponent.

FIG. 3 a is a perspective diagram of an embodiment of a cage.

FIG. 3 b is a cross-sectional diagram of an embodiment of an outercover.

FIG. 4 is an exploded view of an embodiment of a cage.

FIG. 5 is a perspective diagram of another embodiment of a cage.

FIG. 6 a is a perspective diagram of another embodiment of a cage.

FIG. 6 b is a perspective diagram of another embodiment of a cage.

FIG. 6 c is a perspective diagram of another embodiment of a cage.

FIG. 6 d is a perspective diagram of another embodiment of a cage.

FIG. 7 is a perspective diagram of another embodiment of a cage.

FIG. 8 a is a cross-sectional diagram of a downhole tool stringcomponent.

FIG. 8 b is a cross-sectional diagram of a downhole tool stringcomponent.

FIG. 8 c is a cross-sectional diagram of a downhole tool stringcomponent.

FIG. 8 d is a cross-sectional diagram of a downhole tool stringcomponent.

FIG. 9 a is a cross-sectional diagram of a downhole tool stringcomponent.

FIG. 9 b is a cross-sectional diagram of a downhole tool stringcomponent.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

FIG. 1 is a side-view diagram depicting an embodiment of a drill string100 suspended by a derrick 108 in a bore hole 102. A drilling assembly103 is located at the bottom of the bore hole 102 and comprises a drillbit 104. As the drill bit 104 rotates downhole the drill string 100advances farther into the earth. The drill string 100 may penetrate softor hard subterranean formations 105. Data gathered downhole may be sentto a surface data swivel 106 via a transmission system such as the onedisclosed in U.S. Pat. No. 6,670,880 to Hall, which is hereinincorporated by reference for all that it discloses. The data swivel 106may send the data to surface equipment 150. Further, the surfaceequipment may send data and/or power to downhole tools, the drill bit104 and/or the drilling assembly 103. The drill string 100 may comprisea bottom hole assembly 109. The bottom hole assembly 109 may comprise acage 200 (See FIG. 2). The cage 200 may be disposed above the bottomhole assembly 109.

FIG. 2 depicts an embodiment of a downhole tool string component 201.The tool string component 201 may comprise a cage 200. The cage 200 maybe slid over a mandrel 202 of the drill string 100 and may be disposedadjacent other cages of varying purpose and function. The arrangement ofthe variety of cages may be changed by sliding the cages onto themandrel 202 in a different order. The cage 200 may be adapted tofunction as an induction receiver, induction transmitter, acoustic tool,power source, nuclear tool or combination thereof.

In one aspect of the invention, the tool string component 201 maycomprise an induction transmitter 210 and a plurality of inductionreceivers 211. The receivers 211 may be placed in a variety oforientations with respect to each other and to the transmitter 210. Theinduction transmitter 210 is adapted to send an induction signal intothe formation, which generates a formation induction field surroundingthe well bore. The induction receivers 211 are adapted to sense variousattributes of the induction field in the formation. These attributes mayinclude among others, some or all of the following: frequency,amplitude, or phase. The transmitter and the receivers may be powered bybatteries, a turbine generator or from the downhole network. Thereceivers may also be passive. In some embodiments, there may be severalinduction transmitters located along the length of the tool stringcomponent 201. The transmitter 210 and receivers 211 may communicatewith the network through a multiplexor 626 (See FIG. 3 a).

FIG. 3 a is a perspective diagram of an embodiment of a cage 200. Thecage 200 may comprise a stab connection 300 adapted to electricallyconnect the cage with another downhole drill string component 201. It isbelieved that a cage 200 comprising a stab connection 300 on a downholedrill string component 201 may expedite the assembly process of thedrill string 100. A stab connection 300 may also allow the drill string100 to be assembled by placing multiple cages 200 onto a mandrel 202 inany order. In the event of damage to a downhole drill string instrument322, the cage 200 may be removed from the drill string 100 forinspection and/or replacement by sliding it along the mandrel 202.

The stab connection 300 may connect with another component through adock 510 (See FIG. 5). The stab connection 300 may comprise a pluralityof wires 301 extending from a first end 302 of the cage 300. The stabconnection 300 may also comprise a bulkhead connector, boot connector,feed through connector, other electrical connectors known in the art, orcombinations thereof. The plurality of wires 301 may comprise wiresextending individually or sets of wires wrapped together. One wirewithin the plurality of wires 301 may be wired to a separate downholedrill string instrument 322. The separate downhole drill stringinstrument 322 may be individually excitable.

The stab connection 300 may electrically connect to a multiplexor 626.The multiplexor 626 may comprise more inputs than outputs. The downholedrill string instrument 322 may comprise an induction receiver,induction transmitter, Halbach array, battery, acoustic tool, and/ornuclear tool. Each instrument 322 may be independently excitable.Independently excitable instruments 322 may focus an induction field (asin a resistivity tool) or signal (as in a nuclear or sonic tool forexample) into only a portion of the formation 105 adjacent to theexcitable instruments while the remaining portion of the formation 105is minimally affected or not affected at all. Furthermore it is believedthat the ability to concentrate the field in portions of the formation105 adjacent the bore hole 102 will allow for directional measurementsof the formation 105.

The cage 200 may also comprise a shell 320 circumferentially disposedexterior an inner cylinder 1010 and along at least a portion of thelength of the cage 200. The shell 320 may comprise a plurality ofrecesses 321 adapted to house the plurality of instruments 322. Eachrecess within the plurality of recesses 321 may comprise at least onewire from the plurality of wires 301 connectable to the instrument 322.

The shell 320 may be segmented. The shell 320 may be mounted onto theinner cylinder 1010 through a joining mechanism which may comprisebolts, nuts, latches, screws, clips, hinges, adhesives, metallic bondingagents, welds, pins, other joining elements known in the art orcombinations thereof. The shell 320 may also be spring loaded to snaponto the inner cylinder 1010. Segmenting the shell 320 may lead to easyremoval from and assembly onto the inner cylinder 1010.

FIG. 3 b is a cross-sectional diagram of an embodiment of an outer cover380. The cage 200 may comprise a plurality of grooves 340 disposedcircumferentially around the cage 200 and sized to accept a plurality ofrods 341 in each groove within the plurality of grooves 340. Theplurality of grooves 340 and plurality of rods 341 may limit therotation of the cage with respect to the downhole drill string 100 byrestricting the rotation of the cage 200 with respect to the outer cover380. The plurality of grooves 340 and plurality of rods 341 may alsobear a majority of the load exerted on the drill string while downhole.

FIG. 4 is an exploded view of a cage 200. The shell 320 may be mountedto the cage 200 through screws 450 as shown. The cage 200 may comprise aprocessing unit 420. The processing unit 420 may allow for independentoperation of the plurality of instruments 322.

In various embodiments, two or more cages 200 of varying purpose (i.e.nuclear, resistivity, power, etc.) and comprising processor units 420may be stacked within a drill string 100. A signal sent downhole by adownhole network or similar means may call for the operation of aparticular cage 200 and may be picked up by the processor unit 420 ofthat particular cage 200. Stacking the cages 200 may not affect theaddressability of each cage 200, no matter the quantity or arrangementof cages 200. Downhole programming may be unnecessary if each cage 200has its own uniquely identifiable processor unit 420 and thus may beplaced on the drill string 100 in any order and called on by surfaceequipment 150 to perform various functions.

FIG. 5 displays a perspective view of an inner cylinder 1010. In someembodiments, the downhole drill string instruments 322 may be mounteddirectly on the inner cylinder 1010. The inner cylinder 1010 maycomprise a stab connection 300 adapted to electrically connect thedownhole drill string instruments 322 on the inner cylinder 1010 toanother portion of the downhole drill string or to another cage forexample. The stab connection 300 may be received by a dock 510 comprisedwithin the downhole drill string 100. The dock 510 may comprise at leastone port 511 disposed on a second end 303 of the cage 200 and positionedto accept an alignment key 700 (See FIG. 7) disposed within the firstend 302 of another cage 200.

FIGS. 6 a-d show several embodiments of cage 200 comprising variousdownhole instruments 322. FIG. 6 a displays an embodiment of a cage 200comprising induction receivers 211 arranged circumferentially along theouter diameter of the shell 320. The induction receivers 211 may be usedto read a signal induced in a formation by an induction transmitter 212.FIG. 6 b shows an embodiment of a cage 200 comprising a plurality ofinduction transmitters 212 mounted circumferentially along the outerdiameter of a shell 320. The plurality of induction transmitters 212 mayinduce a magnetic field in a formation which may be read by inductionreceivers 211 on another shell 320 on the drill string 100. FIG. 6 cshows an embodiment of a cage 200 comprising a plurality of batteries213. The plurality of batteries 213 may power a downhole component suchas a receiver, transmitter, nuclear tool, sonic tool, motor orcombinations thereof. The stab connection 300 may communicate power fromthe plurality of batteries 213 to the downhole component. FIG. 6 d showsan embodiment of a cage 200 comprising a plurality of nuclear toolcomponents 214. The nuclear tool components 214 may be used to gathercharacteristic data of a formation. In other embodiments, the cage 200may comprise sonic sensors, geophones, hydrophones, accelerometers,inclinometers, pressure transducers, magnetometers, gyroscopes,temperature sensors, gamma ray sensors, neutron sensors, seismicsensors, mud logging devices, resistivity sensors, induction sensors,nuclear sensors, imaging devices, GPS devices, Hall-effect sensors,permeability sensors, porosity sensors, vibration sensors, electricalpotential sensors, a CPU or combinations thereof.

FIG. 7 is a perspective diagram of an embodiment of a cage 200. Thefirst end 302 may comprise an alignment key 700. The alignment key 700may comprise a tapered geometry and/or comprise a round, square, or ovalcross section. The cage 200 may be slid over a mandrel 202 and connectedto an adjacent component by aligning the alignment key 700 with ports511 on the adjacent component which may in turn align the stabconnection 300 with the dock 510.

The cage 200 may also comprise a seal 701 which may restrict the accessof drilling fluid into certain areas. The seal 701 may comprise a ring,band of rubber, washer, foam or combinations thereof. Seals 701 may bemounted on the cage 200 near the first end 302 and/or second end 303.

FIGS. 5 a-d are cross-sectional views of an embodiment of a cage 200comprising individually excitable instruments 322. In some embodiments,these instruments 322 may be excited at once, in pairs, in groups, orindividually.

In some applications it may be desirable to analyze only a portion ofthe formation 105 by exciting individual instruments 322. Where accuracyis critical the drill string 100 may be stopped while instruments 322may be individually activated. Additionally, individual instruments 322may be activated while the drill string 100 rotates. The instruments 322may be activated in a number of different orders. The activation ordersmay include but are not limited to the orders depicted in FIGS. 8 a, 8b, 8 c, and 8 d. The instruments 322 may be activated in a clockwise orcounterclockwise direction.

FIGS. 9 a and 9 b depict different embodiments of induction receivers211. The induction receivers 211 may be independently excitable. Theinduction receivers 211 may also be tunable such that a virtual receiver900 may be created. A virtual receiver 900 may be created when twoadjacent induction receivers 211 adjust their power such that a virtualreceiver 900 can be modeled as being positioned between the twoinduction receivers 211. FIG. 9 a depicts an embodiment of a virtualreceiver 900 that is the result of the data received by two adjacentinduction receivers 211 being equally weighted. FIG. 9 b depicts anembodiment of a virtual receiver 900 that is the result of the datareceived by an induction receiver 902 being weighed more heavily thanthe data received by an adjacent induction receiver 903. The virtualreceiver 900 in this case appears closer to induction receiver 902 thaninduction receiver 903.

Whereas the present invention has been described in particular relationto the drawings attached hereto, it should be understood that other andfurther modifications apart from those shown or suggested herein, may bemade within the scope and spirit of the present invention.

1. A downhole drill string component, comprising: a substantiallycylindrical cage comprising a first end, an outer diameter and an innerdiameter, the inner diameter slideably connectable to a mandrel; a stabconnection originating from the first end; and a plurality of downholedrill string instruments circumferentially disposed around the outerdiameter, wherein at least one of the plurality of downhole drill stringinstruments is independently energized.
 2. The component of claim 1,wherein at least one of the plurality of downhole drill stringinstruments is an induction receiver.
 3. The component of claim 1,wherein at least one of the plurality of downhole drill stringinstruments is an induction transmitter.
 4. The component of claim 3,wherein the induction transmitter comprises a Halbach array.
 5. Thecomponent of claim 1, wherein at least one of the plurality of downholedrill string instruments is a battery.
 6. The component of claim 1,wherein at least one of the plurality of downhole drill stringinstruments is a nuclear tool.
 7. The component of claim 1, wherein atleast one of the plurality of downhole drill string instruments is anacoustic tool.
 8. The component of claim 1, wherein the cage comprises asecond end comprising a dock formed to receive a stab connection.
 9. Thecomponent of claim 1, wherein the cage comprises a shell and an innercylinder, the shell disposed circumferentially and at least partiallyalong the inner cylinder, the shell further disposed intermediate theplurality of downhole drill string instruments and the inner cylinder.10. The component of claim 9, wherein the shell comprises at least onerecess adapted to receive at least one downhole drill string instrument.11. The component of claim 9, wherein the cage comprises a seal disposedon the cylindrical cage.
 12. The component of claim 9, wherein the shellcomprises a plurality of segments.
 13. The component of claim 12,wherein at least two segments are joined through a joining mechanismdisposed at least partially on each segment.
 14. The component of claim1, wherein the cage comprises an alignment key disposed on the firstend.
 15. The component of claim 1, wherein the stab connectionelectrically communicates with a multiplexor.
 16. The component of claim1, wherein the cage comprises a plurality of grooves disposedcircumferentially around the cage.
 17. The component of claim 16,wherein the cage comprises an outer cover comprising a plurality of rodscomprising geometry substantially similar to the geometry of theplurality of grooves.
 18. The component of claim 1, wherein the cage isuniquely addressable.
 19. The component of claim 1, wherein the cagecomprises a processing unit.
 20. A downhole drill string component,comprising: a substantially cylindrical cage comprising a first end, anouter diameter and an inner diameter the inner diameter slideablyconnectable to a mandrel; a stab connection originating from the firstend; and a plurality of downhole drill string instrumentscircumferentially disposed around the outer diameter.